US 5,290,527 A · Molybdenum recovery

Abstract

A process for recovery of molybdenum from residual fractions derived from an epoxidation reaction of propylene with tertiary butyl hydroperoxide in liquid phase with tertiary butyl alcohol, in the presence of soluble molybdenum, which process comprises: Fractionating epoxidation reaction product for obtaining a liquid fraction containing essentially all molybdenum from the reaction product; Contacting the liquid fraction with anhydrous ammonia for forming a precipitate containing the major portion of the molybdenum and a liquid phase containing 500 ppm or less molybdenum; Separating the liquid phase from the precipitated solid; Evaporating the liquid phase under conditions of elevated temperatures and reduced pressure in the presence of 1 to 3% water for separation into an evaporator overhead vapor essentially free of molybdenum and an evaporator concentrate comprising essentially all of the molybdenum fed to the evaporator; Rapidly cooling evaporator concentrate from about evaporation temperature to about room temperature or less for converting the evaporator concentrate into a brittle, fracturable solid which is easier to accumulate and dispose of in an environmentally acceptable manner.

Claims5

Dependent claims

In a method for recovering molybdenum values from the liquid portion of an ammonia-treated, non-distillate residual fraction from a process for epoxidation of olefin with organic hydroperoxide in the presence of a molybdenum catalyst, wherein the ammonia-treated liquid residual fraction is heated to a temperature in the range of about 100.degree. to 300.degree. C. at a pressure in the range of about 1 to 100 mmHg, absolute, in an evaporation zone for forming an evaporator overhead vapor fraction essentially free of molybdenum and comprising about 80 to 95 wt % of the residual fraction, and an evaporator concentrate containing essentially all the molybdenum in the ammonia-treated liquid residual fraction, the improvement which comprises:

(a) maintaining 1 to 3 wt % water in the evaporator overhead vapor fraction sufficient to prevent deposition of solid ammonium salts therefrom;
and
(b) rapidly cooling the evaporator concentrate fraction from evaporation temperatures to about room temperature at a rate of at least about 2.degree. C. per minute, sufficient to convert the evaporator concentrate into a brittle, non-tacky solid at room temperature.

Dependencies are inferred from the claim text.

Molybdenum recovery

Life of this patent

Molybdenum recovery

Life of this patent

Abstract

Claims5